Processing data packet traffic in a distributed router architecture

Abstract

Embodiments of the invention are directed to efficiently processing packet traffic in a system such as a switch or router having a distributed architecture. An internal header is appended to an ingress packet by an ingress packet processing device before the packet is forwarded to a fabric switch of the system. The internal header corresponds to a configuration of an ingress interface over which the packet was received. An egress packet processing device, upon receiving the packet from the switch, processes the packet based on the internal header and a configuration of an egress interface associated with the egress device. Advantageously, some packet tag manipulation operations are performed only at the egress packet processing device; thereby somewhat freeing up ingress packet processing resources.

1 . A method of processing a packet in a system, comprising the steps of:
 receiving the packet at an ingress interface of the system;   adding an internal header to the packet, the internal header corresponding to a configuration of the ingress interface;   switching the packet with the internal header to a device of the system;   determining a configuration of an egress interface associated with the device; and   processing the packet based on the internal header and the configuration of the egress interface.   
     
     
         2 . The method of  claim 1  wherein the step of processing the packet comprises:
 determining if the configuration of the egress interface is of a first type; 
 determining, from the internal header, if the configuration of the ingress interface is of the first type; and 
 removing the internal header from the packet responsive to the configuration of the egress interface and the configuration of the ingress interface not being of the first type. 
 
     
     
         3 . The method of  claim 2  wherein the step of processing the packet further comprises:
 performing the following steps responsive to the configuration of the egress interface not being of the first type and the configuration of the ingress interface being of the first type:
 parsing the packet based on a frame type indicated by the internal header, 
 removing the internal header from the packet, and 
 removing a first tag from the packet. 
 
 
     
     
         4 . The method of  claim 3  wherein the step of processing the packet further comprises:
 performing the following steps responsive to the configuration of the egress interface being of the first type and the configuration of the ingress interface not being of the first type:
 removing the internal header from the packet, and 
 inserting into the packet a second tag corresponding to the configuration of the egress interface. 
 
 
     
     
         5 . The method of  claim 4  wherein the step of processing the packet further comprises:
 performing the following steps responsive to the configuration of the egress interface and the configuration of the ingress interface being of the first type:
 parsing the packet based on a frame type indicated by the internal header, 
 removing the first tag from the packet, and 
 inserting the second tag into the packet. 
 
 
     
     
         6 . The method of  claim 1  wherein the packet is an Ethernet packet. 
     
     
         7 . The method of  claim 3  wherein the first tag is a Virtual Local Area Network (VLAN) tag. 
     
     
         8 . The method of  claim 4  wherein the second tag is a VLAN tag. 
     
     
         9 . The method of  claim 2  wherein the first type is 802.1Q VLAN encapsulation. 
     
     
         10 . An apparatus for processing a packet comprising:
 an ingress device having access to ingress configuration for receiving packets and being operable to receive the packet and add thereto an internal header corresponding to the ingress configuration;   an egress device having access to egress configuration for transmitting packets; and   a switch operable to receive from the ingress device and transmit to the egress device the packet with the internal header,   wherein the egress device is operable to process the packet based on the internal header and the egress configuration.   
     
     
         11 . The apparatus of  claim 10  wherein the egress device is further operable to process the packet by:
 determining if the egress configuration is of a first type; 
 determining, from the internal header, if the ingress configuration is of the first type; and 
 removing the internal header from the packet responsive to the egress configuration and the ingress configuration not being of the first type. 
 
     
     
         12 . The apparatus of  claim 11  wherein the egress device is further operable to process the packet by performing the following steps responsive to the egress configuration not being of the first type and the ingress configuration being of the first type:
 parsing the packet based on a frame type indicated by the internal header, 
 removing the internal header from the packet, and 
 removing a first tag from the packet. 
 
     
     
         13 . The apparatus of  claim 12  wherein the egress device is further operable to process the packet by performing the following steps responsive to the egress configuration being of the first type and the ingress configuration not being of the first type:
 removing the internal header from the packet, and 
 inserting into the packet a second tag corresponding to the egress configuration. 
 
     
     
         14 . The apparatus of  claim 13  wherein the egress device is further operable to process the packet by performing the following steps responsive to the egress configuration and the ingress configuration being of the first type:
 parsing the packet based on a frame type indicated by the internal header, 
 removing the first tag from the packet, and 
 inserting the second tag into the packet. 
 
     
     
         15 . The apparatus of  claim 10  wherein the packet is an Ethernet packet. 
     
     
         16 . The apparatus of  claim 12  wherein the first tag is a Virtual Local Area Network (VLAN) tag. 
     
     
         17 . The apparatus of  claim 13  wherein the second tag is a VLAN tag. 
     
     
         18 . The apparatus of  claim 11  wherein the first type is 802.1Q VLAN encapsulation. 
     
     
         19 . An apparatus for processing an Ethernet packet comprising:
 an ingress device having an ingress configuration for receiving packets and being operable to receive the Ethernet packet and add thereto an internal header corresponding to the ingress configuration;   an egress device having an egress configuration for transmitting packets; and   a switch operable to receive from the ingress device and transmit to the egress device the Ethernet packet with the internal header,   wherein the egress device is further operable to:
 determine from the internal header if the ingress configuration is 802.1Q VLAN encapsulation, 
 remove the internal header from the Ethernet packet, 
 remove a first VLAN tag from the Ethernet packet if the egress configuration is not 802.1Q VLAN encapsulation and the ingress configuration is 802.1Q VLAN encapsulation, 
 insert into the Ethernet packet a second VLAN tag corresponding to the egress configuration if the egress configuration is 802.1Q VLAN encapsulation and the ingress configuration is not 802.1Q VLAN encapsulation, and 
 remove the first VLAN tag from the Ethernet packet and insert the second VLAN tag into the Ethernet packet if the egress configuration and the ingress configuration are 802.1Q VLAN encapsulation. 
   
     
     
         20 . A method of processing an Ethernet packet in a system, comprising the steps of:
 receiving the Ethernet packet at an ingress interface of the system;   adding an internal header to the Ethernet packet, the internal header corresponding to an ingress configuration of the ingress interface;   switching the Ethernet packet with the internal header to a device of the system;   determining an egress configuration of an egress interface associated with the device;   determining from the internal header if the ingress configuration is of a first type;   removing the internal header from the Ethernet packet;   removing a first VLAN tag from the Ethernet packet if the egress configuration is not of the first type and the ingress configuration is of the first type;   inserting into the Ethernet packet a second VLAN tag corresponding to the egress configuration if the egress configuration is of the first type and the ingress configuration is not of the first type; and   removing the first VLAN tag from the Ethernet packet and inserting the second VLAN tag into the Ethernet packet if the egress configuration and the ingress configuration are of the first type.